The aim of the proposed project is to study the physiological mechanisms for the control of food intake and the regulation of body weight. The proposed experiments are concerned with four specific areas. They are 1) the organizational and activational influences of the gonadal hormones upon the hypothalamic mechanisms regulating body weight, 2) the effects of early hypothalamic lesions upon the level of regulated body both during development and in adulthood, 3) the role of midbrain mechanisms in feeding and weight regulation, and 4) the influence of diet palatability in determining the level of maintained body weight.